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Biomedical subjects

F Mimouni

Publications and source records attributed to F Mimouni.

At least 37 records · Page 2Linked to original sources
PubMed1993

Placental calcium transport during acute maternal hypermagnesemia in the rat.

OBJECTIVE: Our aim was to test the hypothesis that maternofetal placental calcium transfer rate decreases in experimentally induced acute maternal hypermagnesemia in the rat. STUDY DESIGN: We measured the unidirectional maternofetal clearance of calcium 45 and chromium 51-ethylenediaminetetraacetic acid across in situ perfused placentas of rats randomized to intravenous treatment with saline solution and magnesium sulfate (n = 5) or to saline solution only (n = 5) before placental perfusion. The maternofetal clearance of chromium 51-ethylenediaminetetraacetic acid provides a measure of placental "porosity" or passive permeability. RESULTS: The mean serum magnesium concentration increased to 5.3 +/- 0.6 mg/dl (2.18 +/- 0.25 mmol/L) in magnesium-infused rats, staying at 1.8 +/- 0.1 mg/dl (0.74 +/- 0.04 mmol/L) in control rats (p < 0.001). Neither the maternofetal clearance of calcium 45 nor that of chromium 51-ethylenediaminetetraacetic acid was affected by acute maternal hypermagnesemia. CONCLUSION: Within the range of hypermagnesemia studied, placental calcium transport remains unaffected.

Animals↗
PubMed1993

Bone mineralization in the first year of life in infants fed human milk, cow-milk formula, or soy-based formula.

OBJECTIVE: To test the hypotheses that (1) bone mineral content (BMC) is similar in infants fed soy-based formula (SBF) and human milk (HM) and higher in infants fed cow milk-based formula (CBF) and (2) serum 1,25-dihydroxyvitamin D, an index of mineral sufficiency, is similar in infants fed formula and infants fed HM. DESIGN: Randomized, prospective study of formula-fed group only. SETTING: Recruitment was in a normal newborn nursery. PATIENTS: 72 infants: 10 given HM, 20 given CBF (Similac), 21 given SBF (Isomil), and 21 given SBF (Prosobee). MEASUREMENTS: BMC and 1,25-dihydroxyvitamin D levels at baseline (days 2 through 7 of life) and at 8, 16, 26, and 52 weeks of age. The BMC was similar in all groups at all times; serum 1,25-dihydroxyvitamin D levels were similar in all groups, except that they were elevated at 8, 16, and 26 weeks in those fed Prosobee. CONCLUSIONS: (1) BMC is similar in SBF-, CBF-, and HM-fed infants and (2) compensatory elevation of serum 1,25-dihydroxyvitamin D concentrations may occur in SBF-fed infants.

Animals↗
PubMed1993

Hypomagnesemia following correction of metabolic acidosis: a case of hungry bones.

Severe symptomatic hypomagnesemia (0.15 mmol/L [0.3 mEq/L]) and hypocalcemia (1.47 mmol/L [5.9 mg/dL]) occurred in a 4-week-old infant coincidental with correction of a severe renal tubular acidosis with alkali therapy. The patient had no evidence of gastrointestinal abnormality and magnesium (Mg) intake was adequate for age and weight. Extreme renal conservation of Mg was observed, supporting the presence of Mg depletion. We suggest that Mg depletion in this infant occurred due to acidosis-induced bone demineralization and that symptomatic hypomagnesemia was precipitated by rapid remineralization accompanying correction of systemic acidosis. This patient represents a novel case of hungry bone syndrome (HBS). Since HBS has not been described previously in patients with acidosis undergoing therapy, several other factors may have contributed to this patient's severe hypomagnesemia, namely, prematurity, twin status, severity of acidosis, rapidity of correction of acidosis, catch-up growth and calcium supplementation. Clinicians should be vigilant for HBS in infants with severe acidosis undergoing alkali therapy.

Acidosis, Renal Tubular↗
PubMed1992

Progression of diabetic retinopathy in pregnancy: association with hypertension in pregnancy.

OBJECTIVE: To test the hypothesis that women with insulin-dependent diabetes and chronic or pregnancy-induced hypertensive disorders are at increased risk for developing retinopathic complications during pregnancy. STUDY DESIGN: One hundred fifty-four women with insulin-dependent diabetes were prospectively followed in an intensive program of diabetes in pregnancy. Ophthalmologic evaluations were obtained through pregnancy and at 6 to 12 weeks post partum, and findings were graded by a standard scale. Association of retinopathic progression with risk factors was tested with chi 2 and multiple logistic regression analysis. RESULTS: Fifty-one women had progression of retinopathy during pregnancy; postpartum regression was observed in 13 women. Changes in glycemic control early in pregnancy, chronic hypertension, and pregnancy-induced hypertension were significantly associated with progression of retinopathy. CONCLUSION: Women with insulin-dependent diabetes who have hypertensive disorders in pregnancy are at increased risk for progression of retinopathy.

Diabetes Mellitus, Type 1↗
PubMed1992

Neonatal hematocrit and maternal glycemic control in insulin-dependent diabetes.

We hypothesized that in infants of diabetic women neonatal hematocrit would correlate with third-trimester maternal glycemic control. Neonatal hematocrit correlated with the maternal total glycosylated hemoglobin level at delivery (r = 0.36; p less than 0.05) but not at 36 weeks of gestation in 32 mother-infant pairs. Improved maternal glycemic control during late gestation may decrease the incidence of neonatal polycythemia.

Blood Glucose↗
PubMed1992

Birth trauma in insulin-dependent diabetic pregnancies.

Infants of insulin-dependent diabetic mothers are considered to be at high risk for birth trauma, presumably due to macrosomia. With current management of diabetes in pregnancy, including strict glycemic control, the rate and the severity of macrosomia should be decreased. The frequent use of ultrasound to assess fetal growth and weight and the use of cesarean delivery in case of fetal macrosomia should further decrease the risk for birth trauma in these infants. We therefore undertook this study to test the null hypothesis that with current management, insulin-dependent diabetic mothers have a rate of birth trauma similar to that of infants of nondiabetic mothers (normal glucose challenge test at 28 weeks' gestation) matched for gestational age at birth, presence or absence of labor, delivery method (vaginal versus cesarean), and race. We studied 118 insulin-dependent diabetic mothers (White classes B-RT) and 354 control subjects (three matches for each insulin-dependent diabetic mother). The rate of birth trauma was 3.4% in insulin-dependent diabetic mothers, not significantly different from controls (2.5%). Logistic regression analysis in which birth trauma was the dependent variable and diabetes, race, presence or absence of labor, mode of delivery (vaginal versus cesarean), infant weight, and infant head circumference were independent variables revealed that only vaginal delivery was a significant risk factor for birth trauma in infants in both groups (p = 0.01). Most frequently observed birth traumas were brachial plexus injury, facial nerve injury, and cephalohematoma. Of the three infants with brachial plexus injury (insulin-dependent diabetic mothers, two; controls, one), two were delivered with use of midforceps.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Effect of chronic maternal dietary magnesium deficiency on placental calcium transport.

Metabolisms of calcium (Ca) and magnesium (Mg) are closely interrelated in the intestine, bone, and kidney. Interaction of Ca and Mg at the placental level, however, is not well defined. The occurrence of decreased bone mineral content and hypocalcemia in infants of hypomagnesemic mothers led us to test the hypothesis that chronic dietary maternal Mg deficiency decreases placental Ca transport. On day 10 of gestation, 20 Sprague-Dawley rats were randomized to a Mg-deficient diet (3.3 mg/day, n = 10) or to a control diet (70 mg/day, n = 10). On day 20 of gestation (term = 22 days), intact placentas were perfused in situ through the umbilical artery and perfusate was collected through the umbilical vein. Calcium 45 (45Ca) and chromium 51-EDTA (51Cr-EDTA) (a diffusional marker for placental membrane integrity) were injected to the dam and steady state maternofetal clearance (Kmf45Ca, microliter/min/g placenta) of both isotopes were calculated. There was no difference in the clearance of 45Ca and 51Cr in both groups (55 +/- 10 vs 57 +/- 16 and 3.2 +/- 0.4 vs 3.6 +/- 0.4, respectively, mean +/- SEM). We conclude that, in the rat, placental Ca transfer is unaffected by chronic maternal dietary Mg deficiency. We speculate that Ca and Mg cross the placenta by independent mechanisms.

Animals↗
PubMed1992

Low bone mineral content in summer-born compared with winter-born infants.

Possible seasonal differences in newborn bone mineral content (BMC) have not been studied. Adult studies show seasonal variations with lower BMC in winter versus summer. Assuming that BMC variations may relate in part to vitamin D status, we hypothesized that newborn BMC would be lower in winter than summer. BMC of one third distal radius was measured in 55 healthy term newborns using a single beam photon absorptiometer [coefficient of variation (CV) for phantom standard 2.1%]. Infants were enrolled during summer (July-September, 1988) and winter (January-March, 1989) for a longitudinal nutrition study. Contrary to our hypothesis, there was a 12% lower BMC in summer versus winter (mean +/- SD 75.94 +/- 17.42 vs. 86.55 +/- 17.54 mg/cm, respectively; p = 0.035). The difference remained significant after controlling for possible race and gender effects (p = 0.02). We conclude that BMC is lower in summer- compared with winter-born infants. Since any seasonal effects on fetal bone are presumably related to effects through the mother, we speculate that if maternal vitamin D status influences fetal bone mineralization, the effect (possible sunshine deprivation in winter) may operate especially in early pregnancy, thus resulting in lower BMC, evident at birth in summer.

Black People↗
PubMed1992

Osteoma cutis as a presenting sign of pseudohypoparathyroidism.

Four unrelated children with osteoma cutis and Albright hereditary osteodystrophy (pseudohypoparathyroidism and pseudopseudohypoparathyroidism) are described. All four patients were normocalcemic when they were first seen with cutaneous ossification. A diagnosis of Albright hereditary osteodystrophy was established on the basis of associated somatic features, radiographic abnormalities, and family history. Progression to pseudohypoparathyroidism was documented in two children who developed hypocalcemia at 2 and 3 years of age, respectively. Early recognition of the skin manifestations of this syndrome and careful follow-up are important to prevent the deleterious effects of hypocalcemia. Osteoma cutis is a common sign of Albright hereditary osteodystrophy in infancy and childhood, and its significance should not be overlooked, even in the normocalcemic patient.

Female↗
PubMed1991

Severe rickets in Lowe syndrome: treatment with continuous nasogastric infusion.

A boy with Lowe syndrome who manifested renal Fanconi syndrome by severe hypophosphatemic rickets, failure to thrive, and metabolic acidosis failed to improve with conventional bolus therapy of phosphate and bicarbonate. He was then placed on home continuous nasogastric infusion of phosphate and bicarbonate in addition to caloric supplementation. Rapid reversal of metabolic acidosis and hypophosphatemia was achieved. There was significant improvement in clinical and radiological signs of rickets and in bone mineral content. After 9 months therapy, his ponderal age improved dramatically from 7.5 to 29.5 months and his statural age from 16 to 26 months. We conclude that continuous nasogastric infusion of phosphorus and bicarbonate is a useful alternative mode of therapy in patients with renal Fanconi syndrome who are resistant to conventional bolus therapy.

Acidosis↗